Memory devices have a wide variety of uses in modern electronic devices, including devices such as cellular phones, personal computers, laptops, personal digital assistants, camcorders, voice recorders, portable storage drives for such devices, and the like. As memory devices become smaller, less expensive to manufacture, and capable of storing larger amounts of information, they become viable products for larger segments of the current electronic technology. Consequently, as consumer demand and available markets for electronic memory increases, additional memory device technologies are developed to fully leverage capabilities of electronic devices in such markets. Flash memory, for example, is one type of electronic memory media that can store, erase and restore data. Furthermore, flash memory, unlike some types of electronic memory, can retain stored data without exposure to continuous electrical power. Flash memory has become a popular device for consumer electronics, due in part to a combination of the high density and low cost of erasable programmable read only memory (EPROM) and electrical erasability introduced with electronically erasable programmable read only memory (EEPROM). In addition to combining these benefits, flash memory is nonvolatile (e.g., flash memory can be removed from a power source without losing stored data). Consequently, it has become a useful and popular mechanism for storing, transporting, sharing and maintaining data.
As flash memory has become more popular as a consumer product, more uses are discovered for such memory. Some uses include storage of sensitive and/or long-term data. For instance, pictures and other memorabilia can be stored by way of flash memory. The long life and storage integrity of flash memory provides an ideal mechanism to store such data. However, even the most robust flash memory can suffer from some drawbacks that can be detrimental to data. One such drawback is called memory cell drift, where a cell level (e.g., corresponding to a level of charge, voltage, and/or current of the cell) that corresponds to a particular program state changes over time. Severe drift can cause data to be lost if the cell level changes to a degree that a desired/intended program state is no longer distinguishable from other program states. Typically such problems occur only over long periods of time. But for sensitive and/or long-term data, such as digital photographs, data integrity may be desired for decades or longer. Accordingly, even slow acting drift can be problematic.